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Diffstat (limited to 'Documentation/hid')
| -rw-r--r-- | Documentation/hid/intel-thc-hid.rst | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/Documentation/hid/intel-thc-hid.rst b/Documentation/hid/intel-thc-hid.rst index dc9250787fc5..8b378c57b5aa 100644 --- a/Documentation/hid/intel-thc-hid.rst +++ b/Documentation/hid/intel-thc-hid.rst @@ -188,6 +188,34 @@ Control register. Reset line is controlled by BIOS (or EFI) through ACPI _RST method, driver needs to call this device ACPI _RST method to reset touch IC during initialization. +2.3 Max input size control +-------------------------- + +This is a new feature introduced in Panther Lake platform, THC hardware allows driver to set +a max input size for RxDMA. After this max size gets set and enabled, for every input report +packet reading, THC hardware sequencer will first read incoming input packet size, then compare +input packet size with the given max size: + +- if input packet size <= max size, THC continues using input packet size to finish the reading +- if input packet size > max size, there is potential input data crash risk during + transferring, THC will use max size instead of input packet size for reading + +This feature is used to avoid data corruption which will cause RxDMA buffer overrun issue for +I2C bus, and enhance whole system stability. + +2.4 Interrupt delay +------------------- + +Because of MCU performance limitation, some touch devices cannot de-assert interrupt pin +immediately after input data is transferred, which cause an interrupt toggle delay. But THC +always detects next interrupt immediately after last input interrupt is handled. In this +case, the delayed interrupt de-assertion will be recognized as a new interrupt signal by THC, +and causes THC to start an input report reading spuriously. + +In order to avoid this situation, THC introduced interrupt delay new feature in Panther Lake +platform, where THC allows driver to set an interrupt delay. After this feature is enabled, +THC will delay this given time for next interrupt detection. + 3. High level concept ===================== |